This invention relates, in general, to transmitter optoelectronic integrated circuits, and more particularly to optoelectronic integrated circuits having monolithically integrated optical emission and drive portions.
Fiber optic transmission systems have emerged as a prominent technology in a variety of disciplines, including: automotive, computer, medical, and communications. Typically, a fiber optic system comprises a transmitting optoelectronic circuit, or transmission source, coupled to a receiver via an optical fiber. Further, in seeking lower cost methods of building optoelectronic systems, manufacturers have begun employing optical fibers made of plastic.
In an effort to exploit the high end communications market, manufacturers of optoelectronic components have leapfrogged the low end communications segment. Hence optoelectronics manufacturers have optimized their products for the high end communications arena, leaving a void in the low end communications market. For instance, most manufacturers of low end optoelectronic components build their optical emissions devices and the circuitry required to drive these devices as separate units. This approach has compelled systems designers who desire to incorporate optical emissions devices into their designs to familiarize themselves with optoelectronic technology.
Further complicating the design process is the inability to directly drive optical emissions devices with systems operating at logic voltage levels compatible with TTL or standard CMOS circuitry. Hence the system logic voltage levels must be translated from those of TTL or standard CMOS to voltage levels compatible with the optical emissions devices. In addition to logic voltage levels, designers must contend with differences in the power supply voltages between the optoelectronics circuitry and the systems circuitry which drive these devices. What is more, there may not only be differences in the voltage level requirements of the power supply but there may also be differences in the polarity requirements of the power supply.
Accordingly, it would be beneficial to have an optoelectronic integrated circuit capable of being driven by logic voltage levels compatible with those of TTL and standard CMOS. Further, it is desirable that in accomplishing this task an improvement in the reliability of the circuitry results. It is further desired that the cost of accomplishing the task of driving an optoelectronic integrated circuit with TTL or standard CMOS voltage levels be minimized. Finally, it would be advantageous for the operation of the optoelectronic integrated circuit to be easily understood by those inexperienced with the characteristics of optoelectronic technology.